It is well known that keratin fibers such as the hair, eyelashes or eyebrows are sensitized or weakened to various degrees by the action of atmospheric agents and of light, development of greasiness, and chlorine, and also by the repeated action of various more or less aggressive treatments, such as permanent waves, straightening, dyeing, bleaching, washing and others. The hair then becomes rough to the touch and is difficult to disentangle and to style. Moreover, the mechanical properties of the keratin fibers, such as tensile strength, breaking load and elasticity, are adversely affected over time.
Compositions can then be applied to these keratin fibers, comprising agents which protect the keratin fibers, such as sunscreens or flavonoids.
As used herein, “agents which protect keratin fibers” mean agents which protect the keratin fibers against aggressive external influences, particularly those described above.
As used herein, “protection of keratin fibers against aggressive external influences” and “protection of keratin fibers”means the reduction in the adverse effect on the physicochemical properties of the keratin fibers, and in particular the tensile strength, breaking load and elasticity, under the action of the external agents. This cosmetic effect is manifested in an improved appearance of the fibers.
However, the (cosmetic treatment) compositions comprising such protective agents are generally aqueous compositions in which the agents must be solubilized. The lack of solubility of these compounds lessens the treatment power of these compositions. Furthermore, this solubility criterion reduces the number of water-insoluble protective agents that can be used for the cosmetic treatment of keratin fibers. This is particularly the case with compounds having a high melting point.